A container body of a van, a van trailer or a freight container in refrigerated, thermal or dry cargo type consists of an inner plate, an outer plate, and a foaming heat preservation layer between the inner plate and the outer plate, in which the inner plate comprises an inner side panel, an inner roof sheet, and an aluminum floor. Since there is a large quantity of water vapor in the refrigerated container body, connections between adjacent components should have a good sealing property. In a usual case, the inner side panel is connected to the inner roof sheet via an angle aluminum which is drawn out through a profile and acts as a connector, the angle aluminum is connected to the inner side panel and the inner roof sheet respectively via blind rivets. However, since there is a gap at the rivets, and even a rivet mandrel has not good sealing property, it is easy for the water vapor in the container body to invade into the heat preservation layer via the gap at the rivets or the rivet mandrel, which reduces the heat preservation effect of the heat preservation layer. In addition, in this traditional connecting manner, the connector is connected to the inner side panel and the inner roof sheet in a mechanical and hard manner. Thereby, during uploading cargo into the container body or downloading cargo out of the container body, the angle aluminum may deform as a roof bow deforms, which would yield a repeated shearing action among the inner side panel, the inner roof sheet, the angle aluminum, and the rivets; with the time elapses, the angle aluminum would loose and the sealing property would further lower, and thus the water vapor in the container body would easily invade into the heat preservation layer and consequently further lower the heat preservation effect. Moreover, for connecting the inner side panel and the inner roof sheet via the angle aluminum, it is usual to install the angle aluminum inside the container body after a general assembly of the container body is finished, and it may require a special clamping tools to fix the angle aluminum and take a large quantity of labor to complete the installation of the rivets, causing waste of time and labor.